20151 ÷ 3 = 6717 R0
No problem, we've got 20151 and 3 for the division.

Step 1:
3 goes into 2 0 times with a remainder of 2.
Write down 0 as next digit of of the result. 
Result so far: 0
Subtract 0 from 2 to get 2.
Bring next digit (0) of the dividend behind the 2 and repeat the process: 20 / 3

Step 2:
3 goes into 20 6 times with a remainder of 2.
Write down 6 as next digit of of the result. 
Result so far: 6
Subtract 18 from 20 to get 2.
Bring next digit (1) of the dividend behind the 2 and repeat the process: 21 / 3

Step 3:
3 goes into 21 7 times with a remainder of 0.
Write down 7 as next digit of of the result. 
Result so far: 67
Subtract 21 from 21 to get 0.
Bring next digit (5) of the dividend behind the 0 and repeat the process: 5 / 3

Step 4:
3 goes into 5 1 times with a remainder of 2.
Write down 1 as next digit of of the result. 
Result so far: 671
Subtract 3 from 5 to get 2.
Bring next digit (1) of the dividend behind the 2 and repeat the process: 21 / 3

Step 5:
3 goes into 21 7 times with a remainder of 0.
Write down 7 as next digit of of the result. 
Result so far: 6717
Subtract 21 from 21 to get 0.

The final result is 6717 with a remainder of 0.